For more than 50 years, the Colombian government battled a leftist rebel group known as the FARC, or Revolutionary Armed Forces of Colombia, in a conflict that claimed 220,000 lives, displaced millions of people and hampered the economy of a country rich in natural resources and human capital.
After several failed attempts, the government and the rebels reached an agreement last week in Havana that could finally end the longest running conflict in the Western Hemisphere. Colombians will vote whether to approve the deal Oct. 2 in a nationwide plebiscite.
In the meantime, the two sides Monday announced a formal cease-fire.
Here's a primer on the history and potential future of the country's largest rebel group:
What is the FARC?
Pedro Antonio Marin, a peasant farmer who went by the alias Manuel Marulanda, or "Sure Shot," founded the rebel group in 1964 after a 10-year civil war known as La Violencia fought between paramilitary groups representing the Liberal, Conservative and Communist parties over control of agricultural lands. It ended with amnesties for leaders and a power-sharing agreement that didn't resolve underlying peasant complaints. The FARC's stated aim was to seek redistribution of land favoring the poor as well as opposition to the presence of multinational companies.
Under Marulanda's leadership, the FARC drew recruits mainly from poor, rural, indigenous and Afro-Colombian communities and universities, growing to an estimated 20,000 armed fighters by the late 1990s.
Marulanda died of natural causes in 2008 at age 77.
What conditions allowed the FARC and other insurgencies to grow?
Colombia had a long history of inequality and repression of peasants by moneyed elites. The victimization of poor farmers was exacerbated by the lack of agrarian reform. Peasants effectively were the slaves of coffee haciendas controlled by rich land owners. The country's mountainous geography that isolates many rural communities meant the state had little influence.
Peasant rebellions date back to the 1930s, when the collapse of agricultural markets and government neglect led to massive rural protests. In the 1940s, a dozen farm communities actually declared their independence from the government by forming "red republics."
The 1958 pact that ended La Violencia excluded poor farmers and labor unions, making extremist groups like the FARC more appealing to the disenfranchised.
Why did the FARC become Colombia's largest, most powerful rebel group?
While up to six insurgent groups operated in Colombia at various times, the FARC had the strongest ties to Colombia's peasantry. In many remote communities where rule of law was weak or nonexistent, the rebels filled the void.
Even now, the poor in many areas turn to the FARC to resolve disputes over property, loans and other matters. The rebels would act as judge, jury and, if need be, executioner in exchange for the loyalty, intelligence and food support from poor petitioners.
Growth accelerated after 1982, when the FARC began to pursue a military takeover and finance it through kidnappings and drug trafficking. The change in strategy helped fill the ranks through better payments to fighters and gave the rebels greater control in the countryside.
When did the FARC achieve its peak military strength?
The FARC inflicted a series of humiliating defeats on the hapless Colombian military during the 1990s by overrunning several bases and taking hundreds of soldiers hostage. By the beginning of President Alvaro Uribe's term in 2002, rebels had encircled the capital, Bogota. They fired rockets at downtown targets during his inauguration ceremony.
What led to the FARC's decline?
The rise of paramilitary militias forced the FARC to retreat from many areas of influence, including the Caribbean coastal areas, in favor of the remote eastern jungle plains and southern border areas. The paramilitaries were formed by wealthy farmers and cattlemen as self-defense forces against the FARC because they felt abandoned by the central government. By the time the militias demobilized in 2006, many had morphed into criminal gangs involved in drugs and extortion rackets.
Another blow was Plan Colombia, the U.S. antiterror and drugs aid program that funneled $10 billion to Colombia's armed forces and social service agencies. Included in the aid was telecommunications monitoring technology that helped Colombia target and kill FARC leaders such as Raul Reyes in 2008, Mono Jojoy in 2010 and Alfonso Cano in 2011.
The 1982 decision to engage in kidnappings and drug trafficking ultimately cost the FARC popular sympathy.
Why did previous peace negotiations fail?
The FARC and the government signed a peace deal in 1984 that led to a three-year ceasefire and the formation of a FARC-allied political party, the Union Patriotica. But the slayings in subsequent years of about 1,000 of the party's office-holders and activists by right wing death squads quashed hopes for peace.
Starting in 1999, President Andres Pastrana held peace talks with the FARC and even consented to a demilitarized "clearance zone" in eastern Colombia for the rebels so they could negotiate. But the talks broke down in 2002.
Why did the FARC finally forsake war and join peace talks in 2012?
The killings of several top FARC leaders by the military and the death of Marulanda crippled the leadership structure. Over the last decade, the modernized Colombian army had the FARC on the run. Desertions in the lower ranks were common.
Convinced that the rebels would never win militarily, outside boosters, including Cuba's Fidel Castro and the late Venezuelan President Hugo Chavez, urged the FARC to seek peace and shift strategy to the political stage.
Polls show Colombians deeply divided over the peace deal. Why are so many expected to vote against it on Oct. 2?
Few families in Colombia are untouched by the war's kidnappings, displacements and extortion involving threats of violence. Although the military and right wing paramilitary groups committed atrocities over the course of the conflict, the public holds the rebels most accountable.
Under the peace deal, rebels would be guaranteed 10 congressional seats for the next two terms and amnesty for certain crimes if they confess. Those terms may be difficult for many Colombians to accept.
As former FARC hostage and presidential candidate Ingrid Betancourt put it to a television interviewer last weekend, many victims are eager for peace but still need time to forgive.
What will be the FARC's future role in Colombian politics?
If voters approve the deal, the FARC will disarm over a six-month period as its fighters move to 23 "relocation zones" and eight rebel camps. The FARC has yet to say what its political party will be, but many think it will be the now-forming peasant-based Marcha Patriotica whose goals involve agrarian reform including redistribution of large land-holdings to poor farmers.